I finally “pondered” options long enough and dove in using several ideas in this thread.
I used an 11”x18”x1/2” poly cutting board cut down to 11”x~10”. Used #12 1 1/2” self-tapping, roofing lag bolts and existing macerator cover mount holes. Put 3/8” nuts between the board and the macerator cover as spacers. Didn’t use the inboard holes. Used original Entegra screws to secure the pump to the board and cut off ~1\8” of each that came through the board. I can replace them easily if needed later.
Also added a Shurflo silencer for the needed hose extension.